Configurable stall injection for interface error checking

Abstract

A system that includes determining whether an interface between sender and receiver devices is defective. For an interface between a sender device and a receiver device: a configured number of stalls can be injected in a communication from the sender device to the receiver device. Based on the counted number of stalls being less than an injected number of stalls or exceeding the injected number of stalls by more than a threshold level, the interface can be identified as defective with respect to stall state counting. Based on the counted number of stalls being the same as the injected number of stalls or exceeding the injected number of stalls by not more than the threshold level, the interface can be identified as non-defective with respect to stall state counting.

1 . A method comprising:
 for an interface between a sender device and a receiver device:   injecting a configured number of stalls in a communication from the sender device to the receiver device;   determining whether a stall condition occurs in the communication;   counting a number of detected stalls;   based on the counted number of stalls being less than an injected number of stalls or exceeding the injected number of stalls by more than a threshold level, identifying the interface as defective with respect to stall state; and   based on the counted number of stalls being the same as the injected number of stalls or exceeding the injected number of stalls by not more than the threshold level, identifying the interface as non-defective with respect to stall state.   
     
     
         2 . The method of  claim 1 , wherein injecting the configured number of stalls comprises:
 injecting the configured number of stalls for a duration based on a configuration.   
     
     
         3 . The method of  claim 2 , wherein the injecting the configured number of stalls for a duration based on a configuration comprises:
 injecting the configured number of stalls for the duration timed according to a counter.   
     
     
         4 . The method of  claim 1 , wherein injecting the configured number of stalls comprises:
 injecting the configured number of stalls based on a pseudo-random number generator and a reference value.   
     
     
         5 . The method of  claim 4 , wherein the injecting the configured number of stalls based on a pseudo-random number generator and a reference value is based on a linear feedback shift register output compared to the reference value. 
     
     
         6 . The method of  claim 1 , wherein the injecting the configured number of stalls comprises:
 modifying a data valid state from the sender device and   modifying a ready to receive data state from the receiver device.   
     
     
         7 . The method of  claim 6 , wherein the modifying the data valid state from the sender device comprises:
 providing the data valid state unmodified based on the configured number of stalls being zero and   providing the data valid state to indicate no valid data during injection of a stall.   
     
     
         8 . The method of  claim 6 , wherein the modifying the ready to receive data state from the receiver device comprises:
 providing the ready to receive data state unmodified based on the configured number of stalls being zero and   providing the ready to receive data state to indicate not ready to receive data during injection of a stall.   
     
     
         9 . A non-transitory computer-readable medium comprising instructions stored thereon, that if executed by one or more processors, cause the one or more processors to:
 during a test of a graphics processing unit (GPU) comprising a sender device, an interface, and a receiver device:
 injecting a configured number of stalls in a communication from the sender device to the receiver device via an interface; 
 determining whether a stall condition occurs in the communication; 
 counting a number of detected stalls; 
 based on the counted number of stalls being less than an injected number of stalls or exceeding the injected number of stalls by more than a threshold level, identifying the interface as defective with respect to stall state; and 
 based on the counted number of stalls being the same as the injected number of stalls or exceeding the injected number of stalls by not more than the threshold level, identifying the interface as non-defective with respect to stall state. 
   
     
     
         10 . The computer-readable medium of  claim 9 , wherein injecting the configured number of stalls comprises injecting the configured number of stalls for a duration based on a configuration. 
     
     
         11 . The computer-readable medium of  claim 9 , wherein injecting the configured number of stalls comprises injecting the configured number of stalls based on a pseudo-random number generator and a reference value. 
     
     
         12 . The computer-readable medium of  claim 9 , wherein the injecting the configured number of stalls comprises:
 modifying a data valid state from the sender device and   modifying a ready to receive data state from the receiver device.   
     
     
         13 . The computer-readable medium of  claim 12 , wherein the modifying the data valid state from the sender device comprises:
 providing the data valid state unmodified based on the configured number of stalls being zero and   providing the data valid state to indicate no valid data during injection of a stall.   
     
     
         14 . The computer-readable medium of  claim 12 , wherein the modifying the ready to receive data state from the receiver device comprises:
 providing the ready to receive data state unmodified based on the configured number of stalls being zero and   providing the ready to receive data state to indicate not ready to receive data during injection of a stall.   
     
     
         15 . The computer-readable medium of  claim 9 , wherein the test of the GPU occurs pre-silicon or post-silicon. 
     
     
         16 . An apparatus comprising:
 a sender device;   a receiver device; and   an interface between the sender device and the receiver device, wherein:
 the interface is to inject a configured number of stalls in a communication from the sender device to the receiver device via the interface; 
 the interface is to determine whether a stall condition occurs in the communication; 
 the interface is to count a number of detected stalls and store the counted number of detected stalls for access by a tester to determine whether the interface is defective with respect to stall state or non-defective with respect to stall state. 
   
     
     
         17 . The apparatus of  claim 16 , wherein to inject the configured number of stalls, the interface is to inject the configured number of stalls for a duration of time based on a configuration. 
     
     
         18 . The apparatus of  claim 17 , wherein the interface comprises a pseudo-random number generator configured to cause injection of the configured number of stalls and a down counter to control the duration of time of stall injection. 
     
     
         19 . The apparatus of  claim 16 , wherein to inject the configured number of stalls, the interface is to:
 provide a data valid state from the sender device to the receiver device unmodified based on the configured number of stalls being zero and   modify the data valid state from the sender device to the receiver device to indicate no valid data during injection of a stall.   
     
     
         20 . The apparatus of  claim 16 , wherein to inject the configured number of stalls, the interface is to:
 provide a ready to receive data state from the receiver device to the sender device unmodified based on the configured number of stalls being zero and   modify the ready to receive data state from the receiver device to the sender device to indicate not ready to receive data during injection of a stall.